Question

Which of the following pairs of numbers is matched with its correct least common multiple? Select all that apply.

The least common multiple of 5 and 8 is 40.

The least common multiple of 3 and 9 is 27.

The least common multiple of 2 and 3 is 5.

The least common multiple of 4 and 6 is 12.

Answer 1

Answer: A. The LCM of 5 and 8 is 40 & D. The LCM of 4 and 6 is 12

Step-by-step explanation: When you find the LCM, you basically have to list the factors of that number, and then find the least common multiple. (I'm gonna use the first one as an example)

5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50

8: 8, 16, 24, 32, 40, 48, 56, 64, 72, 80

(Now I'm going to use the second one)

3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30

9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90

You're probably thinking that "why didn't you put 27", well, as you can see, 3 and 9 does have a common multiple of 27, but we are looking for the least common multiple, and 3 and 9 have another common multiple which is 9 which is less than 27.

So in summary, when you find the LCM, all you have to do is list out the factors, and find the least common multiple.